What Is Block Height?

The block height of a particular block is defined as the number of blocks preceding it in the blockchain. A blockchain is an encrypted database that records a ledger of transactions sequentially in data structures known as blocks. Blockchains are used as the underlying technology for cryptocurrencies such as Bitcoin.

Block height can either reference the location of a transaction that has been completed in the past's location in the blockchain, or refer to the present length or size of a blockchain. A block height chart is indicative of how steadily new blocks are being discovered on the blockchain as time passes, amid varying mining difficulty levels.

As of April 2021, the block height for the Bitcoin blockchain exceeds 677,350 blocks, with approximately 144 new blocks added daily.

Key Takeaways

  • Block height refers to a specific location in a blockchain, measured by how many confirmed blocks precede it.
  • The current block height of a blockchain is an indication of its current size or time in existence.
  • Decentralized consensus algorithms typically function by agreeing to mine the chain with the longest block height.


Understanding Block Height

A blockchain contains a series of sequential blocks, hence the name blockchain. These blocks are essentially data units that are used to store transactional information of the network. Each block contains a secure and public record of the transactions that occurred or were validated in the interval between the previous block and the block in question.

The very first block on a blockchain is called the genesis block. It has a block height of zero, as no blocks precede it in the blockchain. The total height of the blockchain is taken to be the height of the most recent block, or the highest block, in the chain.

Block height is also calculated sometimes as the current length of the blockchain minus one.

Special Considerations: Bitcoin Mining

As a way to understand block height, it is useful to understand the process of cryptocurrency mining and how new blocks are added to the blockchain. Let's look at the case of Bitcoin. Here, a mathematical problem is linked with each block.

Miners are constantly processing and recording transactions as part of the process of competing in a type of race. They race to "complete the current block" in order to win Bitcoins. When a winning miner is able to solve it, the answer is shared with other mining nodes and it is validated. Every time a miner solves a problem, a newly minted 12.5 BTC (Bitcoin currency symbol) is awarded to the miner and enters the circulation.

The first record in that next block is a transaction that awards the winning miner (who completed the previous block) the newly minted BTC. The difficulty of the mathematical problem regulates the creation rate of new Bitcoins since new blocks can’t be submitted to the network without the answer. Based on the fact that it takes around 10 minutes on average to solve the problem, approximately 12.5 new Bitcoins are minted every 10 minutes.